题目

Github: OmitByType

从 T 中选取一组属性，这些属性的类型不可分配给 U 。

type OmitBoolean = OmitByType<{
  name: string
  count: number
  isReadonly: boolean
  isEnable: boolean
}, boolean> // { name: string; count: number }

解题思路

略。

答案

type OmitByType<T, U> = {
  [P in keyof T as T[P] extends U ? never : P]: T[P]
}

验证

interface Model {
  
name
: string
  
count
: number
  
isReadonly
: boolean
  
isEnable
: boolean
}

type 
cases
 = [
  
Expect
<
Equal
<
OmitByType
<Model, boolean>, { 
name
: string, 
count
: number }>>,
  
Expect
<
Equal
<
OmitByType
<Model, string>, { 
count
: number, 
isReadonly
: boolean, 
isEnable
: boolean }>>,
  
Expect
<
Equal
<
OmitByType
<Model, number>, { 
name
: string, 
isReadonly
: boolean, 
isEnable
: boolean }>>,
]

参考

• 映射类型 Mapped Types
• 通过 as 进行按键重映射 Key remapping via as
• 条件类型 Conditional Types
• keyof 和查找类型 keyof and lookup types